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/*
* Copyright (C) 2001 Nikos Mavroyanopoulos
*
* This file is part of GNUTLS.
*
* GNUTLS is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* GNUTLS is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*/
#include <gnutls_int.h>
#include <gnutls_errors.h>
#include <cert_b64.h>
#include <auth_x509.h>
#include <gnutls_cert.h>
#include <cert_asn1.h>
#include <cert_der.h>
#include <gnutls_datum.h>
#include <gnutls_gcry.h>
#include <gnutls_privkey.h>
#include <gnutls_global.h>
#include <gnutls_pk.h>
#include <debug.h>
static gnutls_datum* _gnutls_get_tbs( gnutls_cert* cert) {
node_asn *c2;
gnutls_datum * ret;
opaque *str;
int result, len;
int start, end;
if (asn1_create_structure( _gnutls_get_pkix(), "PKIX1Implicit88.Certificate", &c2, "certificate")!=ASN_OK) {
gnutls_assert();
return NULL;
}
result = asn1_get_der( c2, cert->raw.data, cert->raw.size);
if (result != ASN_OK) {
gnutls_assert();
asn1_delete_structure(c2);
return NULL;
}
result = asn1_get_start_end_der( c2, cert->raw.data, cert->raw.size,
"certificate.tbsCertificate", &start, &end);
asn1_delete_structure(c2);
if (result != ASN_OK) {
gnutls_assert();
return NULL;
}
len = end - start + 1;
str = &cert->raw.data[start];
ret = gnutls_malloc(sizeof(gnutls_datum));
if (ret==NULL) {
gnutls_assert();
return NULL;
}
if (gnutls_set_datum( ret, str, len) < 0) {
gnutls_assert();
gnutls_free(ret);
return NULL;
}
return ret;
}
/* we use DER here -- FIXME: use BER
*/
static int _gnutls_get_ber_digest_info( const gnutls_datum *info, MACAlgorithm *hash, opaque* digest, int *digest_size) {
node_asn* dinfo;
int result;
opaque str[1024];
int len;
if (asn1_create_structure( _gnutls_get_pkcs(), "PKCS-1.DigestInfo", &dinfo, "digest_info")!=ASN_OK) {
gnutls_assert();
return GNUTLS_E_ASN1_ERROR;
}
result = asn1_get_der( dinfo, info->data, info->size);
if (result != ASN_OK) {
gnutls_assert();
asn1_delete_structure(dinfo);
return GNUTLS_E_ASN1_PARSING_ERROR;
}
len = sizeof(str)-1;
result =
asn1_read_value( dinfo, "digest_info.digestAlgorithm.algorithm", str, &len);
if (result != ASN_OK) {
gnutls_assert();
asn1_delete_structure(dinfo);
return GNUTLS_E_ASN1_PARSING_ERROR;
}
*hash = -1;
if ( strcmp(str, "1 2 840 113549 2 5")==0) { /* MD5 */
*hash = GNUTLS_MAC_MD5;
} else
if ( strcmp(str, "xxxxxx")==0) { /* SHA1 ID */
*hash = GNUTLS_MAC_SHA;
}
if (*hash==-1) {
#ifdef DEBUG
fprintf(stderr, "HASH OID: %s\n", str);
#endif
gnutls_assert();
return GNUTLS_E_UNIMPLEMENTED_FEATURE;
}
result =
asn1_read_value( dinfo, "digest_info.digest", digest, digest_size);
if (result != ASN_OK) {
gnutls_assert();
asn1_delete_structure(dinfo);
return GNUTLS_E_ASN1_PARSING_ERROR;
}
asn1_delete_structure(dinfo);
return 0;
}
/* if hash==MD5 then we do RSA-MD5
* if hash==SHA then we do RSA-SHA
* m is modulus
* e is public key
*/
int
_gnutls_pkcs1_rsa_verify_sig( gnutls_datum* signature, gnutls_datum* text, MPI e, MPI m)
{
MACAlgorithm hash;
int ret;
opaque digest[MAX_HASH_SIZE], md[MAX_HASH_SIZE];
int digest_size;
GNUTLS_HASH_HANDLE hd;
gnutls_datum decrypted;
if ( (ret=_gnutls_pkcs1_rsa_decrypt( &decrypted, *signature, e, m, 1)) < 0) {
gnutls_assert();
return ret;
}
/* decrypted is a BER encoded data of type DigestInfo
*/
digest_size = sizeof(digest);
if ( (ret = _gnutls_get_ber_digest_info( &decrypted, &hash, digest, &digest_size )) != 0) {
gnutls_assert();
return ret;
}
gnutls_free_datum( &decrypted);
if (digest_size != gnutls_hash_get_algo_len(hash)) {
gnutls_assert();
return GNUTLS_E_ASN1_PARSING_ERROR;
}
hd = gnutls_hash_init( hash);
gnutls_hash( hd, text->data, text->size);
gnutls_hash_deinit( hd, md);
if (memcmp( md, digest, digest_size)!=0) {
gnutls_assert();
return GNUTLS_E_PK_SIGNATURE_FAILED;
}
return 0;
}
CertificateStatus gnutls_verify_signature(gnutls_cert* cert, gnutls_cert* issuer) {
gnutls_datum signature;
gnutls_datum* tbs;
if ( issuer->subject_pk_algorithm == GNUTLS_PK_RSA) {
signature.data = cert->signature;
signature.size = cert->signature_size;
tbs = _gnutls_get_tbs( cert);
if (tbs==NULL) {
gnutls_assert();
return GNUTLS_CERT_INVALID;
}
if (_gnutls_pkcs1_rsa_verify_sig( &signature, tbs, issuer->params[1], issuer->params[0])!=0) {
gnutls_assert();
gnutls_free_datum( tbs);
return GNUTLS_CERT_NOT_TRUSTED;
}
gnutls_free_datum(tbs);
return GNUTLS_CERT_TRUSTED;
}
#ifdef DEBUG
fprintf(stderr, "PK: %d\n", issuer->subject_pk_algorithm);
#endif
gnutls_assert();
return GNUTLS_CERT_INVALID;
}
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